Moving from a TAL100....

[Rick_It]

At the moment I have a TAL100RS. It gave me a lot of great observations of planets, the moon and some double stars.

However I want something bigger to observe also DSO.

The refractor will be se sold to finance the new scope, toghether with its mount (an EQ3.2). At first, I thought at a 10" dobson from GSO. However I can't stop to think at a Orion Optics VX8L, may be in the second hand market (although they are very rare to find in Italy, but I'm really budget constrained), to be used with an alt/az mount.

By going with the GSO I'm very afraid of its performance in hi-res, which is something I really like. This for two reasons: (1) optical quality and (2) the movement of the dobson. I'm also a bit afraid I will never use a scope that weight 16kg plus 12kg for the base. 

Any suggestion?

[scarp15]

The Orion Optics UK VX8L on dobsonian mount, is a lovely scope, very nicely engineered and with very fine optics and is highly portable. They do come up, in the UK second hand occasionally at attractive cost - though if a seller was prepared to ship to Italy could perhaps be a problem. The value of the pound has dropped against the euro fairly steadily, I do not know if this would make an at retail purchase (ask for a 5% discount to) a bit more attractive?  

Here is mine set up on my local allotment (observatory) patch. 

 

 

 

 

[spaceboy]

From what I gather the optics in the older GSO were a notch below those in the Sky-watcher and most definitely below that of Orion optics so I'd say go with the 8" OO.

[Rick_It]

Thanks for the replies! Ideally, it would be optimal the VX10, light enough and good optics but of course very expensive.

Between OO8L and GSO/SW 10", I understand it's difficult to say how much I will gain in hi-res and how much I will loose in DSO with the OO.

I will check the for sale section of this website, let's see if something comes out.

PS: I received an ultimatum from my wife: this has to be the last scope for some years. I bought and sold a C5 first, and now the TAL 100. Also for this reason, I'm a bit uncertain about what to do.

[mikeDnight]

4 hours ago, Rick_It said:

At the moment I have a TAL100RS. It gave me a lot of great observations of planets, the moon and some double stars.

However I want something bigger to observe also DSO.

The refractor will be se sold to finance the new scope, toghether with its mount (an EQ3.2). At first, I thought at a 10" dobson from GSO. However I can't stop to think at a Orion Optics VX8L, may be in the second hand market (although they are very rare to find in Italy, but I'm really budget constrained), to be used with an alt/az mount.

By going with the GSO I'm very afraid of its performance in hi-res, which is something I really like. This for two reasons: (1) optical quality and (2) the movement of the dobson. I'm also a bit afraid I will never use a scope that weight 16kg plus 12kg for the base. 

Any suggestion?

It's a serious business changing scopes and worthy of serious thought. What's good for one is not necessarily good for another, and getting a scope that's too much hassle to use because it is too big or heavy can soon take the joy out of your observing. Moving up in optical quality rather than in aperture might be the way to go if a bulky scope is a potential problem.  It's a hobby and all about enjoyment at the end of the day! The scope you have, if used with good quality eyepieces, is very nice. However, an ED apochromat of the same aperture will be so much better, especially if you appreciate sharp, high definition viewing. And if you're well dark adapted, they are very capable on dso's too.

You don't have to spend the earth either, as the SW Pro ED apo refractors are very reasonably priced, and can at times be found on the second hand market.

Mike

 

 

Mike.

[Ben the Ignorant]

8 hours ago, Rick_It said:

By going with the GSO I'm very afraid of its performance in hi-res

Why should you be VERY afraid of its high-res rendition? That fear could be justified if most of GSO gear was proven junk, but it's not the case. Lots of GSO newtonians have been evaluated by stargazers and in the lab, and the majority was good or very good. If GSO was scary they would barely sell anything, and wouldn't be on your wish list to begin with.

I've bought four GSO dielectric diagonals (kept them all except the one I offered as a gift), and a 300 f/5 GSO dob with its finder and 25mm Plössl. All the diagonals are excellent, better than a William in direct comparo, and equal to Sky-Watcher. The little Plössl is as good as 50° eyepiece can be, edge-blackened and all, but I obviously use wide-angle units instead. The only defect I could find in the whole package is a lightly misaligned cemented doublet in the finder's eyepiece. Stars at the edge are a little less sharp on one axis, but still ok on the other axis; in practice it changes nothing.

The 300 is super-sharp and does not scatter, showed the central star in the Eskimo nebula with such ease another observer was stunned to see it so clear and sharp. Star-test is symmetrical, smooth, no zones, no roughness, no stig, no spherical. Lunar, solar and planetary detail is reduced by turbulence only. Besides, 94% reflectivity is standard in GSO dobs. The focuser is so well machined, light reflected off its anodized chassis is split in rainbow colors, like it happens on a CD's microgrooves.

Beware that some people who downplay affordable optics do so to justify the big money they spent on boutique optics. Just two days ago I watched a guy on YouTube saying that this and that affordable (electric) guitars do not sound very good, but while he played them, you could hear they did sound very nice compared to the expensive ones he played later. Said they didn't play well either, but you could plainly see he was very comfortable playing them! Then he only praised the costly guitars as it if was obligatory for stuff that costs a lot. The more he spent, the more he praised. Linear review according to price.

[Rick_It]

Mike, an ED or APO is totally excluded. As I said in the first post, (1) I love hi-res but I want to start to observe also DSO and (2) I'm quite budget constrained. So I want at least a 200mm if not a 250mm, non an 80mm ED.

You have one point rights:

getting a scope that's too much hassle to use because it is too big or heavy can soon take the joy out of your observing.

And that's the reason why I am a bit afraid of the 250 dobson: weight and dobsonian mount. I have a small "garage-made" (but with big roller bearings) alt-az mount, I know it and I believe it will be a joy to use a mount like that with a newtonian.

 

[John]

I have an Orion Optics 12" F/5.3 newtonian with their "research grade" optics in it. A friend of mine has the Revelation (GSO made) 12" F/5 dobsonian. On the deep sky I'm sure his scope performs just as well as mine from the reports he makes on here and the discussions we have had. On high resolution targets it's possible that my scope might just have the edge but it would be a close run thing.

As you are primarily interested in extending your deep sky capability (as I understand it) I would certainly be happily considering both GSO and Skywatcher optics if I were you

 

[Timebandit]

1 hour ago, John said:

I have an Orion Optics 12" F/5.3 newtonian with their "research grade" optics in it. A friend of mine has the Revelation (GSO made) 12" F/5 dobsonian. On the deep sky I'm sure his scope performs just as well as mine from the reports he makes on here and the discussions we have had. On high resolution targets it's possible that my scope might just have the edge but it would be a close run thing.

As you are primarily interested in extending your deep sky capability (as I understand it) I would certainly be happily considering both GSO and Skywatcher optics if I were you

 

 

My understanding from what I read over the years that GSO, used in revelation and meade light bridge, mirrors did seem to have a problem some years back regarding quality control over there optics ability and mirror coatings, with regards to quality control issues. Therefore the skywatcher back then did seem to have an edge as it was believed that you where more likely to get a "good one". 

From what I have read lately that GSO seem to of sorted out the quality control issues and produce  a much better mirror and therefore GSO, synta mirrors (skywatcher) seem to be on a much more level playing field when it comes to mirror opics nowerdays . 

But one thing I would like to see as I don't think it is done at present. Is that skywatcher and revelation re assure their customers giving a guarantee of the quality of the mirror in there scope. Even if the assurance came in the fact that the scope was guaranteed to have a mirror of 1 / 4pv and 0.82 strehl or better in place. I think this would then at least show a potential purchasers that their intended scope had a quality optical mirror in place and that therefore the telescope was of good optical performance.  I certainly would think this would be of benefit to manufacturers and customers a like.

And if you want the scope for DSO then go for aperture. Aperture Rules on DSO. Just ask the Dob Mob why they want scopes as big as possible 18" 20"22" as they want aperture for DSO

I hope the above helps☺

[scarp15]

If your budget is quite restraint then a Skywatcher Skyliner 200p dobsonian, no doubt about it. If your budget is more flexible, consider the OOUK VX8L dobsonian for their standard hilux coating and top grade option 1/10 PV wave mirrors. For this option though, be prepared to wait a couple of months for your order to be complete / shipped.

[John]

4 hours ago, Timebandit said:

But one thing I would like to see as I don't think it is done at present. Is that skywatcher and revelation re assure their customers giving a guarantee of the quality of the mirror in there scope. Even if the assurance came in the fact that the scope was guaranteed to have a mirror of 1 / 4pv and 0.82 strehl or better in place. I think this would then at least show a potential purchasers that their intended scope had a quality optical mirror in place and that therefore the telescope was of good optical performance.  I certainly would think this would be of benefit to manufacturers and customers a like.

Really what we want to know is the whole system strehl I'd have thought, rather than just the primary ?. Nobody seems to provide this though.

If they did have reports then cherry picking would be rife I'd have thought .......

 

[Moonshane]

You really don't need incredible optics for any observing to be rewarding. My favourite big scope is my 16" f4 dobsonian but it's big and bulky and as a result I tend to use my 12" f4 a lot more. I am not sure the OOUK show massively improved images over the synta options like Skywatcher etc but they can be a bit better. The main benefit for me is the lighter weight of OOUK scopes and also the fact you can get f4 versions which are a lot more compact. 

[Rick_It]

Thanks for all the replies. Give me 5-6 days to think about it

[Moonshane]

OK, but no more 

[Moonshane]

Ps I should add that when I bought my 12" f4 about three years ago the mirror had pin holes in the coatings indicating a need for a recoat at some point - the scope is over 20 years old.   I am still enjoying the excellent views attend probably will for some time to come before actually getting it done.

[Commanderfish]

I think an OOUK VX around the 10" size would be very easy to handle, the aluminium makes them very light, and you can move the base and the OTA separately. Fast to set up despite the size.

However, a 5" Apo might suit you well, or if you are into DSOs primarily then a good 6" Achro.  For £875 you can get a used 127mm ES Apo triplet, there is one on sale an ABS (and here I think?) right now.  I have one and it's great, I' m not letting mine go.  I also have a 6" Altair Starwave Achro which is slightly better for DSO - more aperture, slightly wider field.  Those can be had for £550 used or £700 new.  There is some CA on planets but it is very mild for an Achro.

If you want one all rounder that's easy to handle, I'd go for a 5" Apo Triplet (7.5Kg).  Only thing is, you will need a slightly beefier mount.  I would go for a Teleoptics Alt Az Giro unless you are imaging, just so smooth and fast, and you can use two scopes at once.  Not expensive.

[Rick_It]

Thanks everybody. I was able to find a VX8L second hand and I immediately jumped on it.

I will build my own dobsonian base.

[Stu]

12 minutes ago, Rick_It said:

Thanks everybody. I was able to find a VX8L second hand and I immediately jumped on it.

I will build my own dobsonian base.

Or perhaps......

 

[Rick_It]

I will think about it, thanks.

BTW, if I would like to remove the mirror, how can I do it?

[Stu]

23 minutes ago, Rick_It said:

I will think about it, thanks.

BTW, if I would like to remove the mirror, how can I do it?

Why are you looking to remember be the mirror?

There should be three screws holding the cell in place, you would also need to remove the bottom ring first I think.